JK Rowling, author of the Harry Potter books, was outed at the weekend as the author of The Cuckoo's Calling, which she published under the pseudonym Robert Galbraith. Sales of the book have now rocketed and it has gone to the top of the Amazon bestseller chart.

The revelation that JK Rowling is the pseudonymous author of a well-reviewed debut detective novel has put the publishing world in a tizzy. Maxine Frith goes on the trail of the industry’s tantalising secret